An optically based instrument for in-situ analysis of multiple chemical components in bioreactors will be developed and applied to monitor key components in hybridoma cell fermentation processed used for producing monoclonal antibodies. Monoclonal antibodies have become valuable agents for new cancer therapy and diagnostic methods.. The in situ analyzer employs a novel design integrating recent advances in opto- electronic technology to provide a multiple component analyzer which eliminates interference from biofouling of exposed optical surfaces. The in situ probe design for multiple component analyzer will be compatible with steam sterilization. In the Phase I program, the cell density monitor will be calibrated and evaluated in a research bioreactor to simultaneously monitor one nutrient and one product compound in a hybridoma fermentation process. The in situ analyzer will find commercial applications in monitoring nutrients, products and undesirable byproducts for improved process control and productivity in industrial bioreactors used for production of monoclonal antibodies as well as other bio-pharmaceuticals. PROPOSED COMMERCIAL APPLICATIONS: Applications of the in-situ monitor would be monitoring of nutrients, products and byproducts in industrial bioreactors used for production of monoclonal antibodies, other biopharmaceuticals and commodity. This would include production, pilot and research scale bioreactors.